1. Field of the Invention
The present invention relates to an object, a method, or a manufacturing method. The present invention relates to a process, a machine, manufacture, or a composition of matter. One embodiment of the present invention particularly relates to a semiconductor device, a display device, a light-emitting device, a power storage device, a driving method thereof, and a manufacturing method thereof one embodiment of the present invention particularly relates to a secondary battery, a secondary battery module, and a power feeding system.
2. Description of the Related Art
In recent years, portable information terminals typified by smartphones and tablet terminals and mobile devices such as notebook computers and portable game consoles have been actively developed. Further, wearable devices such as smart glasses and smart watches have also been extensively developed. For example, Patent Document 1 discloses a smart watch capable of monitoring the physical activity of the user. Note that in this specification and the like, portable information terminals, mobile devices, wearable devices, and the like are all included in electronic devices.
Users often carry a plurality of electronic devices, for example, a smartphone, a tablet terminal, and a smart watch.
Most of such electronic devices include secondary batteries, which can be repeatedly charged and discharged. Since portable information terminals and wearable devices are expected to be reduced in weight and size, they have difficulty including high-capacity batteries, which tend to be large and heavy. Accordingly, the duration of use is tended to be limited.
The battery can be replaced as needed with a backup battery that is carried, or can be frequently charged through a cable. However, carrying more electronic devices is troublesome and might impair the merits of portable information terminals or wearable devices.